Quote:
Originally Posted by S Keith
It depends on the goal. If the goal is to use the least amount of gas per kWh, then using the ICE for any charging is folly. Generators are designed for power production at constant rpm in mind. They have a near linear efficiency to power relationship. They are MORE efficient at 100% than they are at 50%. Propulsion ICE aren't. They are designed for efficiency while propelling a vehicle, and they have a variable mass/fuel flow, rpm and power relationship.
The ONLY way this would be viable is if you made the charging occur AT the peak efficiency point for power and rpm of the ICE. Under all conditions, the ICE would NEVER beat the generator in terms of fuel burned per kWh due to the larger mass and increase inefficiencies. Additionally, the battery would need to be VERY robust to handle this charge current as you'd likely be charging the 10kWh battery in under an hour.
The only place the propulsion ICE would beat the generator is in pollutants. Generators are dirty.
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As far as robust charging ability, my Pacifica hybrid is nothing special but can recharge at up to about 85kw using the onboard motor generator although I don't know how long as that's what it allows max braking regen. The onboard charger can only go 6.6kw so if recharging with an external generator it would only need to be about a 14hp one but that's more a limitation to the size of the onboard charger installed which is reaching the limits of normal 240 outlets found in garages. Obviously if it can regen at over 10 times the rate, the battery is capable of a faster than 6.6kw recharge. So the 260hp inboard motor (or whatever it is, the non akitson versions like 285 hp) if able to constantly recharge at say 60kw would have that battery full in 15 mins. So why carry an extra $4000 300 pound generator in the bed to maybe save a gallon and take 6-8 times as long?